Document Detail


Neuronal nitric oxide synthase protects against myocardial infarction-induced ventricular arrhythmia and mortality in mice.
MedLine Citation:
PMID:  19770398     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Neuronal nitric oxide synthase (nNOS) is expressed in cardiomyocytes and plays a role in regulating cardiac function and Ca2+ homeostasis. However, the role of nNOS in cardiac electrophysiology after myocardial infarction (MI) is unclear. We hypothesized that nNOS deficiency increases ventricular arrhythmia and mortality after MI. METHODS AND RESULTS: MI was induced in wild-type (WT) or nNOS(-/-) mice by ligation of the left coronary artery. Thirty-day mortality was significantly higher in nNOS(-/-) compared with WT mice. Additionally, nNOS(-/-) mice had impaired cardiac function 2 days after MI. Telemetric ECG monitoring showed that compared with WT, nNOS(-/-) mice had significantly more ventricular arrhythmias and were more likely to develop ventricular fibrillation after MI. Treatment with the L-type Ca2+ channel blocker verapamil reduced the incidence of arrhythmia and ventricular fibrillation in nNOS(-/-) mice after MI. To assess the role of nNOS in Ca2+ handling, patch-clamp and Ca2+ fluorescence techniques were used. Ca2+ transients and L-type Ca2+ currents were higher in nNOS(-/-) compared with WT cardiomyocytes. Additionally, nNOS(-/-) cardiomyocytes exhibited significantly higher systolic and diastolic Ca2+ over a range of pacing frequencies. Treatment with the NO donor S-nitroso N-acetyl-penicillamine decreased Ca2+ transients and L-type Ca2+ current in both nNOS(-/-) and WT cardiomyocytes. Furthermore, S-nitrosylation of Ca2+ handling proteins was significantly decreased in nNOS(-/-) myocardium after MI. CONCLUSIONS: Deficiency in nNOS increases ventricular arrhythmia and mortality after MI in mice. The antiarrhythmic effect of nNOS involves inhibition of L-type Ca2+ channel activity and regulation of Ca2+ handling proteins via S-nitrosylation.
Authors:
Dylan E Burger; Xiangru Lu; Ming Lei; Fu-Li Xiang; Lamis Hammoud; Mao Jiang; Hao Wang; Douglas L Jones; Stephen M Sims; Qingping Feng
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-09-21
Journal Detail:
Title:  Circulation     Volume:  120     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-10-06     Completed Date:  2009-10-23     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1345-54     Citation Subset:  AIM; IM    
Affiliation:
Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada N6A5C1.
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MeSH Terms
Descriptor/Qualifier:
Animals
Apoptosis
Arrhythmias, Cardiac / etiology*,  mortality,  prevention & control*
Calcium / metabolism
Calcium Channels, L-Type / physiology
Coronary Vessels / pathology
Electrocardiography
Mice
Mice, Inbred C57BL
Mice, Knockout
Monitoring, Physiologic
Myocardial Infarction / complications*,  prevention & control*
Myocardial Ischemia / physiopathology
Nitric Oxide Synthase Type I / deficiency,  genetics,  metabolism
Superoxides / metabolism
Telemetry
Ventricular Dysfunction, Left / etiology
Chemical
Reg. No./Substance:
0/Calcium Channels, L-Type; 11062-77-4/Superoxides; 7440-70-2/Calcium; EC 1.14.13.39/Nitric Oxide Synthase Type I

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